ARTICLE: Synthetic oil vs Mineral oil

This is a discussion on ARTICLE: Synthetic oil vs Mineral oil within On modifying a car, part of the Team-BHP Advice category; While reading the first page of the thread I came across a query which asked the users to justify the ...

While reading the first page of the thread I came across a query which asked the users to justify the benefits of switching from mineral to synthetic oil. Here's my experience:

I have a Santro Xing (2003) model, which has clocked 67K till date. I got it secondhand when it was 32K old about three years back. I switched from mineral to semi-synthetic at about the 50K interval. The default oil change interval is 10K. After the first switch I changed the oil at 12K interval. So I have had the semi-synthetic oil filled twice. Following are the direct consequences I have noticed:

1. Engine has become much smoother, eager and I can easily push it to three digit speeds on expressways. It doesn't feel restricted in any way.

2. In each tank fill I have been measuring the FE. I used to get a consistent figure of 13+ earlier, after switching to the semi-synthetic oil I have started getting 16+.

3. I drive around 90km every day, five days a week. My monthly running is 1800kms. At 13kmpl I would spend approx Rs. 8446/- every month on fuel. At 16kmpl, the spend comes down to Rs. 6863/- With petrol at Rs. 61/- per litre, this translates into a saving of Rs. 1583/- If I stick to the prescribed oil change interval, I would have to change oil every five months. This means I stand to save Rs. 7915/- over a period of five months. Each time I change oil, it costs me Rs. 1400/- including oil/filter and labour. So I still get a net saving of about Rs. 6000, or a little more than Rs. 1000/- per month.

Folks, can you please advise if shifting to Synthetic oil from Mineral can change the oil consumption pattern in the car? Our santro is now at 67k km. At 60k service, I changed to Mobil1 0W40 synthetic oil from the earlier mineral oil (15W40). I check the oil level every 3k km's and after last oil change, the oil had to be topped up twice by about 300/400ml each time. That's a total of 700ml consumption in about 7k km's. Never had oil levels drop earlier. No oil leakages as well.

I am trying to figure out what could be the reason. Car runs fine, no black smoke. Mileage is decent at 19-20 (w/o AC, highway). Could it be due to 0W40 oil which is too thin? Will choosing 5W50 help next time? If no solution comes up, I will have to shift down to semi-synthetic next time. Please advise. Thanks in advance.

@amit, I switched to semi-synthetic at around 55K mark on my Santro (which was 7 years old then). Have had one more change since then. No dip in the oil level, no topping up required. I doubt if using a fully synthetic oil would make it any worse.

What I did notice was that immediately after the switch the oil turned black within a couple of weeks. I ran it till 12K more, and then replaced it again. Now the oil is still retaining most of its original colour. So the first time I switched, it must have got some of the residue of the mineral oils out of the engine.

I suggest you wait till your second oil change and see if the oil consumption still happens.

1. Engine flushing is suggested everytime a swith to synth and vice-versa is planned.

Not sure about that. Engine flush is not guaranteed to work, specially on older engines with a high mileage. Go for it only if you are sure that's the only thing left to try, and be prepared for an engine overhaul job in case things go wrong (not during the flush, but as a result of the flush).

For a worry-free experience I would prefer to run shorter bursts (5K or thereabouts) on synthetic oil. That should clean up all the sludge that needs to be cleaned up.

Not sure about that. Engine flush is not guaranteed to work, specially on older engines with a high mileage. Go for it only if you are sure that's the only thing left to try, and be prepared for an engine overhaul job in case things go wrong (not during the flush, but as a result of the flush).

For a worry-free experience I would prefer to run shorter bursts (5K or thereabouts) on synthetic oil. That should clean up all the sludge that needs to be cleaned up.

Well, for an old engine (>50k) which has not been flushed before (or additives like bardahl added), I would recommend the above too. I had posted similar earlier in the thread after doing a lot of reading and thinking over this.

Status Update: Had changed to 5W40 Motul synthetic @ ~74k service. Wanted to change oil after 5-6k, but only managed to service it past Saturday @ ~82K. The oil drained out was completely black (while the new oil is light brown). This confirmed that I should have probably already changed oil 2k earlier. After oil change, engine is running smoothly and slightly less audible now, feeling a bit freer. Its not as pronounced as when I switched from mineral to synthetic. The FE is indeed on the avg 1-1.5 kmpl more than before the switch as I reported earlier in mainly city with part free road driving...

I recently switched to Motul synthetic in my cedia and the engine was flushed before the change. The problem is that most people add flush when the oil level is at its max. For eg, the cedia takes 3.8L of oil and when you add say another 500ml of flush, it exceeds the capacity and takes it up to 4.3L. So when you run the engine with overfilled oil, it damages the seals and gaskits. Its always advisable to drain about a Litre of oil and the add flush.

Once you flush the oil, its recommended to add 2-3 Litres of fresh oil (Mineral will do as well) and run the engine on fresh oil for 10-15 mins. This will ensure that most of the sludge is drained with the fresh oil. After draining the oil to its last drop, add the synthetic oil.

Also, the car's engine is flushed as per HM-Mitsubishi's recomended schedule, guess its every 20k but its just for a few mins and thats the reason, even mineral oil didnt go complete black after 10k kms.

Also, the car's engine is flushed as per HM-Mitsubishi's recomended schedule, guess its every 20k but its just for a few mins and thats the reason, even mineral oil didnt go complete black after 10k kms.

So HM prescribes regular flushing for Cedia unlike for the Lancer ? What they did for Lancer is add Bardahl mild agent to the engine oil but no flushing process done..

1. Engine flushing is suggested everytime a swith to synth and vice-versa is planned.

Not any more. Modern age oils whether mineral or synthetic are completely mixable and there is absolutely no sludge formation on that account. Flushing on a new engine in any case serves no purpose.

Quote:

Originally Posted by honeybee

Not sure about that. Engine flush is not guaranteed to work, specially on older engines with a high mileage. Go for it only if you are sure that's the only thing left to try, and be prepared for an engine overhaul job in case things go wrong (not during the flush, but as a result of the flush).

For a worry-free experience I would prefer to run shorter bursts (5K or thereabouts) on synthetic oil. That should clean up all the sludge that needs to be cleaned up.

^^+1 Completely agree.

Except for the shorter bursts. I prefer to change my first fill of synthetic oil at approx half of the recommended mileage, say at 10K kms instead of the recommended 20K, but then it is a personal choice.

Quote:

Originally Posted by lancer_rit

So HM prescribes regular flushing for Cedia unlike for the Lancer ? What they did for Lancer is add Bardahl mild agent to the engine oil but no flushing process done..

Hey lancer_rit,
I do not think that is what gaurav_chopra meant. As I understand he went in for the flushing as his car has a fair amount of kilometers on the odometer with mineral oil. Though it is not a necessity and certainly not recommended by Mitsubishi.

Hi all.. I have a swift vdi abs. Just got the 3rd free service done and have the engine oil changed to shell helix fully synthetic 5w40. Just wanted to confirm that I am using the right oil for my car, can gurus tell whether I am ok to use this as even after going through lots of threads, i had the option to choose from either shell helix 5w40 or mobil 1 5w50. I dint find much difference but have a little bit of smoother fell and also my car revs better than earlier. Low end torque is much better and reving beyond 3k rpm is better than before (though I maintained below 2.25k rpm till 10k km and do 3k and little more only on highways). The shop guy said that shell helix 5w40 is better than mobil 1 5w50. Just concerned on the different bettwee 40 and 50 in 5w40 and 5w50. Please advice so that I will have better sleep on seeing your advice on this..

Essentially the 5w indicates the lowest temperature at which the oil can be safely used, i.e. retains its viscosity and the other number, 40 or 50, indicates the highest temperature at which the oil can retain its viscosity. So an oil graded 5w40 will retain its viscosity as long as the temperatures are between 5 and 40 degrees. 5w50 would be able to retain viscosity for 10 more degrees beyond the 5w40.

The best option is to check your owner's manual which will give you the recommended grade for the oil to be used in your car. As long as you buy a branded multigrade oil within the manufacturer specs, you should be fine.

Essentially the 5w indicates the lowest temperature at which the oil can be safely used, i.e. retains its viscosity and the other number, 40 or 50, indicates the highest temperature at which the oil can retain its viscosity. So an oil graded 5w40 will retain its viscosity as long as the temperatures are between 5 and 40 degrees. 5w50 would be able to retain viscosity for 10 more degrees beyond the 5w40.

I don't think the higher number indicates temperature. Will it be only 40 degrees c inside a working engine?

Hi all.. I have a swift vdi abs. Just got the 3rd free service done and have the engine oil changed to shell helix fully synthetic 5w40. Just wanted to confirm that I am using the right oil for my car, can gurus tell whether I am ok to use this as even after going through lots of threads, i had the option to choose from either shell helix 5w40 or mobil 1 5w50. I dint find much difference but have a little bit of smoother fell and also my car revs better than earlier. Low end torque is much better and reving beyond 3k rpm is better than before (though I maintained below 2.25k rpm till 10k km and do 3k and little more only on highways). The shop guy said that shell helix 5w40 is better than mobil 1 5w50. Just concerned on the different bettwee 40 and 50 in 5w40 and 5w50. Please advice so that I will have better sleep on seeing your advice on this..

Satish - more than the grade, I think it's important to use diesel specific oil for diesel engine and petrol specific for pertol. The oils you mentioned above are all petrol specific (API-SM). But for diesel they all are API-CF. The only Diesel specific synthetic I know if is Mobil Delvac 1 5W40. That's API CI4+ rated in India. Else there are good CI4 rated minerals like Delvac MX etc. Diesel specific oils have high detergent contents which can deal with the soot generated by oil burning mill. I would rather use a Diesel specific mineral (and change every 5k km's) than using a petrol specific synthetic in a diesel mill (my personal view). With respect to the grade both 5W40 and 5w50 are good enough for indian driving conditions.

Essentially the 5w indicates the lowest temperature at which the oil can be safely used, i.e. retains its viscosity and the other number, 40 or 50, indicates the highest temperature at which the oil can retain its viscosity. So an oil graded 5w40 will retain its viscosity as long as the temperatures are between 5 and 40 degrees. 5w50 would be able to retain viscosity for 10 more degrees beyond the 5w40.

The best option is to check your owner's manual which will give you the recommended grade for the oil to be used in your car. As long as you buy a branded multigrade oil within the manufacturer specs, you should be fine.

Honeybee - 5, 40 or 50 are not real tempratures degrees, these are numbers which indicate the temp tolerance of the oil. IIRC a 15wxx oil is good enough for temps as low as -5`C.